Aquaculture	Fish farming, ie controlled breeding of fish or shellfish (typically in fresh water or sheltered coastal marine environments).
Beam trawls	Nets with heavily weighted "tickler chains" on the foot rope, dragged along or just above the sea bed. Used for industrial fishing and for catching plaice, sole and other flat fish. Damaging to fragile benthic organisms and may lead to a reduction in biodiversity.
Benthic	Fish and other organisms that live on the sea bed.
Black fish	Fish landed illegally at night or in small unregulated harbours (fish are typically undersized or from quotas that have already been exceeded).
Box	See Closed boxes.
By-catch	Any organism that is caught in addition to the target fish. Some by-catches are marketable although much is discarded.
CFP	Common Fisheries Policy. Introduced in 1983 as a 20-year programme for fisheries management in EU waters.
Closed boxes	Designated areas of sea closed to certain types of fishing, or to vessels over a certain size.
Cod end	Narrow-necked bag at the end of a trawl-net in which the fish collect. Larger mesh sizes or open panels are sometimes incorporated in the top of the cod end to allow some of the larger (spawning) fish to escape.
Control rule	A form of medium-term management strategy in which TACs are pre-determined formulaically in relation to stock levels.
Days at sea	See Fishing effort.
Demersal	Fish living near the sea bottom (eg cod, halibut, ling and turbot) (cf pelagic).
Depleted	Stock that has been very badly reduced, making any fishing activity economically unviable.
Discards	Fish and other organisms disposed of at sea (typically because they are non-target species or below minimum landing size, or because the quota for that species has been exhausted).
Drift nets	Long nets used to catch pelagic fish. Nets are typically 3-4 m deep, suspended from a floated "headline" with a weighted foot rope to keep it vertical, and may be up to 50 km in length (current EU restriction is 2.5 km in length). Fish are caught by the gills. This is a controversial fishing method because of the high proportion of by-catches in some fisheries, particularly of small cetaceans. These can be somewhat reduced by submerging the headline and by incorporating large open panels at regular intervals along the net.
Eco-labelling	Labelling of products or commodities to indicate that they satisfy certain environmental criteria.
Effort controls	See Fishing effort.
Ecosystem approach	A fisheries management system which considers the overall marine environment and the effects of commercial fishing on established food chains.
Exclusive Economic	Zone that reaches up to 200 nautical miles from shore.
Zone (EEZ)
Fishing capacity	The potential of a fishing boat to catch fish.
Fishing effort	The amount of fishing exerted by a fishing vessel. This should be proportional to the percentage of total stock taken each year. A reduction in fishing effort (effort control) can be achieved by increasing the minimum mesh size to permit at least one mature age group to escape; another method is to limit the time spent on fishing (days at sea).
Fishing mortality rate	Mortality caused by fishing, in addition to natural mortality. A rate of no more than twice the natural mortality is thought desirable; in EU waters it can be as much as 4 or 5 times as high.
Fully exploited	Fishing which is being carried out around the maximum sustainable yield.
Gadoid	Fish of the cod family (Gadidae), eg cod, haddock, whiting, saithe and Norway pout.
Hague Preference	Adjusts the CFP quotas to give some preference to coastal communities that are particularly dependent on the fishing industry.
High Seas	The area beyond the outer limit of any Exclusive Economic Zone (EEZ).
Industrial fishing	Large-scale fishing for low-value fish (eg sprat, pout and sandeel) to produce fish meal, oils and fat. In the EU, notably by Denmark.
ITQ	Individual Transferable Quota. A fisheries management system where each boat is allocated, or purchases, a portion of the national stock quota. ITQs could be traded between boats to reflect actual catches, and thereby reduce the need for unnecessary discards of marketable fish.
Longline fishing	The use of baited hooks on long lines anchored just above the sea bed, to catch demersal species of fish.
MAGPs	Multi-Annual Guidance Programmes. EU programmes in which fleet capacity reduction targets are laid down for each Member State.
MLS	Minimum Landing Size. Regulation minimum sizes, usually based on the length of the fish and set to reduce the catch of immature individuals. In EU waters many fish species reach MLS before they become sexually mature and are caught before being able to spawn.
Mollusc dredgers	Dredgers that cut through the top 20-30 cm of substrate and remove the animals inhabiting it (eg to harvest cockles and scallops). Such deep ploughing of the seabed may cause long-term environmental damage.
Multi-Annual TACs	TACs set for more than one year at a time, to avoid end of year problems when fish have to be discarded until the new quota year commences. Application of this policy requires longer term forecasts of stock levels to be made, with potentially high margins of error.
No-take zone	An area of the sea closed to all fishing (cf Closed boxes).
Pelagic	Fish and other organisms living in the upper layers of the sea (eg tuna, herring, mackerel and pilchard) (cf Demersal).
Pole-and-line fishing	Practice in tuna fisheries where shoals of fish are lured to the boats and lines with live bait.
Precautionary approach	Fisheries management term equivalent to the "precautionary principle", as used in environmental protection policy generally—ie a presumption against taking action which has the potential to harm the environment, even where scientific certainty is lacking.
Purse-seine	Bag-shaped fishing net, the opening of which can be closed.
Quota hopping	Where vessels of one nationality register in another country in order to gain access to its fishing quota.
Ranching	The enhancement of natural fisheries by artificially rearing young fish to be introduced to the wild.
Relative stability	The principle within the CFP that the total volume of allowable catch is shared among Member States in a manner which assures each State relative stability of fishing activities taking one year with another.
Seine-net	Net with floats at the top and a weighted bottom edge, used for encircling fish.
Straddling stocks	Fish stocks which migrate between areas of the sea governed by different nations, or between governed and non-governed areas.
Structural funds	The various Community funds, financed by the EU budget with matching contributions from Member States, through which aid is directed towards less developed areas of the EU.
TAC	Total Allowable Catch. A component of the CFP designed to achieve a specific fishing mortality rate (eg if so many tonnes of fish x are caught this year then the fishing mortality rate of y will be achieved). TACs are set each year by estimating the number of fish available in each age group, based either on scientific data ("analytical TAC") or on estimates from historical catch data ("precautionary TAC").
Trawling	Method of fishing using a seine-net or trawl-net.
Trawl-net	Bag-shaped net with wide mouth held open and dragged along the seabed.
Year class	All those fish of a particular stock spawned in any one year. For example: "0-group" are fish in their first year of life; "1-group" are fish in their second year of life etc.
6-12 mile zone	The part of the 12 mile limit within which others having a historic right may fish as well as vessels of the coastal state.
12 mile zone	The area of sea under the jurisdiction of the coastal state.